Yes, you should rustproof your car — but at the right price

If you want to keep your car for a long time, rustproofing should be a no-brainer. But don't be fooled by the dealership upsell

by
Lorraine Sommerfeld | October 27, 2014

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To rustproof or not to rustproof, that is the question. Whether ‘tis nobler in the metal to suffer The snow and slush of outrageous winter, Or to take arms against a sea of brine.-With a nod to William Shakespeare

There should be no question. You really should rustproof.

If you bought your car new, once they had you trapped in the finance office, rustproofing was one of the big upsells. A dealer will highly recommend you have your car rustproofed, and I agree with them. I just don’t agree that it should cost 500 bucks, or 750, or a grand if they really saw you coming.

First. If you plan on ditching your car at the end of a lease, don’t bother rustproofing. It can be someone else’s problem, which sounds mean but it’s true. But if you’re going to keep this car – and cars are lasting longer than ever – or sell it privately at some point, rustproofing is your friend. One caveat: if you opt for rustproofing, take it to a place that specializes in it. It may look simple, but one lazy application by a poorly trained technician means your car is vulnerable.

Rustproofing has changed over the years, but the concept is basically the same: keep moisture away from metal to prevent corrosion. Depending on your vintage, you might recall a time when people used motor oil as an undercoating. The principle was good but such practice could compromise electrical components of the car as well as be extremely messy.

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Times have changed and that old oil concept has been replaced with a tar-based spray – undercoating – which effectively forms a hardened barrier to the underneath of your car. You’ll need yearly inspections to check for things like cracking, which can allow moisture to become trapped and become a problem. This is the usual rustproofing that a car dealer will be selling you; a local Ziebart quoted me $249 for this based on a passenger car.

When we think of rust and cars, we often imagine the bad old days when nobody wondered if their car would rust, they only wondered when.

You could choose a dripless oil spray, which forms a hardened wax-type barrier. This covers more area than the tar-based, as holes will be drilled into door panels and other areas so the oil can access more interior regions of the car. If cracks or chips form, this can let in water and hold it there, inviting possible corrosion, though yearly inspections are advised to prevent this. I was quoted Ziebart’s price for this service at $125 (should be done annually), with a combination of this and the tar-based undercoating running $400 with a 10-year warranty, needing annual inspections costing $50.

A drip oil spray treatment is used by Krown Rust Control, where I took my car for a hands-on demonstration. Like the dripless version, a series of holes are drilled into your car to augment factory access points. A light oil mixture is atomized with compressed air to form a chemical bond with the metal while displacing any existing moisture. The entire bottom of your car is then sprayed; you’ll experience a little dripping after the application, but the spray is very fine and the aftermath is short-lived. They recommend doing it each year. Cost is $120 for most passenger cars. Rust Check also does a drip oil at similar cost.

Prevention is always cheaper than cure, and your car is no different. The thing about rust? It starts in places you can’t see, and it starts long before you know it. When we think of rust and cars, we often imagine the bad old days when nobody wondered if their car would rust, they only wondered when. As manufacturers have moved to more alloys and galvanized steel and zinc coatings, they’ve been able to guarantee – usually to the five-year point – that your ride won’t rust. While it’s true from the outside looking in things are much improved, if you put it up on a hoist, you’ll get a whole other story.

Frames and suspension systems are vulnerable, as well as every spot weld and bend and hinge. Salt can start deteriorating those expensive electronic components. In the rust-belt – areas that experience harsh winters – municipalities lay down brine solutions (magnesium chloride) that are effective for safety, but take an immense toll on your car. The GTA has also been using a beet juice solution that is slightly less corrosive, but all of it is designed to stick to road surfaces, which means it also sticks to the underside of your car. Running it through a carwash will only remove a portion.

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When Krown let me help rustproof my car at their head office in Stouffville, Ont., I learned it may not be a difficult procedure, but you want someone attentive and thorough doing it. Drilling holes into your car may seem counter-intuitive, but they’re drilling in specific areas to maximize access and they warranty their work.

It’s a scare tactic to tell you that rustproofing your new car will void your manufacturer warranty, and Krown’s warranty is comprehensive and will cover repairs up to the value of the vehicle. “If a customer brings a vehicle in from new, our annually renewable warranty will stay in place as long as they want to have the vehicle treated. We have customers with vehicles that are 20 years old and still under warranty with us,” says vice-president Jeremy Young. Wherever you go, look for a warranty like this.

A few places will still do a grease rustproofing job for you, which is a great rust deterrent but more costly and not as readily available.

You could also opt for an electronic box some dealers are happy to sell you for upwards of $700 – installed – but you shouldn’t because I’ve never seen any science to prove they work, and the theory is based on the submerged part of steel bridges. So, I guess if you drive a submarine, go for it.

It’s never too late to start rustproofing your car, and remember: it’s what you can’t see that should concern you.